This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. C. elegans as a model organism is well suited for studies in aging due to its short life span and easily controlled mating. The Jakobs lab has worked extensively on C. elegans and aging, most recently working on the role of oxidative stress. They, with other have developed the OxICAT system for mapping the redox active thiol proteome. Their conclusions show that while oxidative stress and aging both lead to comparable levels of reversibly oxidized cysteine residues, target proteins are different. However, their current methods can only map cysteines oxidized to disulphides and not cysteines oxidized to sulfunic or sulfonic acids. In conjunction with the Jakobs lab, we propose to use Sulfur XANES to map the total sulfur oxidation state and the amount of irreversible sulfur oxidation that happens as a result of the aging process compared to that of oxidative stress.